Google image "Les Dawson Ada" to get a sense of the mental picture Ada conjures up for me (and many of my generation, I'd guess). It's a pretty name but it's always linked with Les Dawson.
Freya is really nice and while I often think having siblings with matching initials is a bit twee, that's not the case with Finley and Freya - that works well. You'll also save money on name-tags for school uniform.